FDG–PET Imaging in the Investigation of Homonymous Hemianopia in a Patient With MELAS Syndrome

Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome is a rare congenital disorder of mitochondrial DNA. Patients with MELAS syndrome present with a range of clinical symptoms including headaches, hearing loss, visual defects, and hemiparesis. We report a case of a previously asymptomatic 21-year-old male who presented with recurrent headache, seizures, and right homonymous hemianopia. Investigations included brain MRI, which indicated bilateral occipital white matter and cortical signal abnormality and fluorodeoxyglucose (FDG)–PET brain imaging which demonstrated markedly reduced metabolism in the occipital lobes. The patient was treated with corticosteroids and coenzyme Q and his clinical symptoms have improved.